Burglar-alarm system



March so 1926. 1,578,980 i G. .F. GASSER BURGLAR ALARM SYSTEM Filed Dec. 15, 1922 2 Sheets-Sheet 1 i I I /0 l ZZ 7 14/1; QXMZQ March 30 1926. 1,578,980 7 G. F. GASSER BURGLAR ALARM SYSTEM glar " In .addi

- test switches Patent d-Mar. 30.1926. 1 UNITED STATES, PATEN T OFFICE.

eormrnmn r. a, or ATLANTA, GEORGIA, AssIeNon TO ANNIE masses, or

- -'A'DL.A.NTA, enonem.

nuneLAn-ALAmr sYsrnN. Application fled December 15, 1922. Serial No. 607,049.

To all whom it may concern:

Be it known that I, Go'rrrnmn a citizen of the United States, residing at Atlanta, in the county of'Fulton and State of, Georgia, have invented a certain new and useful Improvementin Burglar-Alarm Systems, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings.

This invention relates to combined burand fire alarm systems. 7 My invention is embodied in the provision of a system which may be used asa burglar 'or fire alarm comprising the use of a normally cldsed circuit, and two normally open circuits, an alarm inone of the normally open circuits and a common source of electrlcal invention con-templates the arrangement. of-

supply for all of said circuits. The

the circuits in such manner that the open; ing of the closed circuit or the closing of v the open circuit actuates the alarm.

'tion, -my invention provides for a cabinet wherein thevarious controls may be centrally located, and wherein suitable may be mounted for enabling an authorized. person to determinethe exact circuit or loop in which the break or short circuit has occurred. This is particularly advantageous in that, the exact loop, or station, ma be quickly ascertained and the source 0 difiiculty remedied in the most ex peditious manner.

Other characteristics of m invention are embodied in suitable safety evices'for permitting the disconnection of the system for repairs or other adjustments without sound-' ing the alarm, and for preventing the S111? reptitious handling; of the controls when the system is in workingv order. I

The particular arrangement of the vanous devices for carrying out the ob ects of my invention will be-hereinafter more fully set forth in the following description, which pertains to the accompanying drawings, and the essential features will be summarized in the claims.

In the drawings, Fig. 1 is an elevation of two'windows havingloops thereon forming. system embodying my 1n'-.

part of a circuit vention; Fig. 2 is a vertical section through a cabinet having devices therein for operating the system; Fig. 3 is a wiringdiagram for connecting the apparatus shown in Fig. 2.

'1, I have s My invention is particularly directed tov ward the use of a normally closed circuit, the opening of which sounds an alarm in a normally open circuit. Accordingly, in Fig. own one circuit as embodied in loops 10 and 11 which are connected to wires 12 and Hand another circuithaving loops14 and 1 5 which are connected to wires 16 and 17, respectively. These loops are preferably strips windowpanes, but in addition to this form of loop, I may also employ butt or rub contacts on doors, windows, chestlids, or other closures whenever desired. In case of fire the tinfoil strips will be melted, and the closed circuit will be opened. which will? cause the alarm to be sounded. These 'yarious loops may also be connected to doors, chests, and the like, but for purposes of illustration, I have indicated only two such circuits. I

The battery and-electrically operated devices for causing the alarm to be sounded when the normally closed circuit isopen, are adapted to be housed in a cabinet 20 which may be provided with a hinged cover of tinfoil secured to the 21, as shown In Fig. 2. These devices comprise test switches 23 and 24, a ldck switch wire 17, wire 18, wire late 38, wire 39, coil 26, wire 40 and thence ack to battery. A. J With this arrangement, as soon as the cover of the cabinet is closed, the circuits through the 'loops are also closed, and the solenoid26 is energized, thus holding the armature 33 in contact point 34 against the force of a retractile sprin 41. It is, stood that swltches 23. and 24 .are normally open and are placed across the lines, as llldl'.

' cated in Fig. 3..

engagement with the ofcourse, under- Whenever any of the closed circuits are open, either by the breaking of one of the loops, such as by heat from fire, or forced entrance, or opening of the cabinet, then the coil 26 is de-energized,-whereupon the armature 33 is drawn upwardly by the spring 41, and intoenga ement with a contact point 45. This closes t e alarm circuit, thug automatically causing the alarm 50 to be sound ed. The alarm continues to sound even though the normally closed circuit is again closed, such as by the closing of a window which may have een forced open, since the spring 41 holds the armature in engagement with the coil 26.

When the alarm circuit is closed current flows as follows :Battery A, wire 30, ground 31, ground 32, armature 33, contact point 45, wire 46, alarm 50, wire 47, lock switch 48, movable contact 49, stationarycontact 51, wire 52, wire 40, and then back'to the battery.

If desired, the alarm circuit may be manu ally opened, after it is once closed, by the operation of a lock switch, indicated generally in Fig. 2 at 25. This may be controlled by a key from a point outside the cabinet. The mechanism actuated by the lock switch may control the operation of an arm 55 to euits, whereby ary which one end of a link 56 is attached. The other end of the link may be connected to the switch member 48 which carries the rub contact members 49, 57 and 58, respectively.

These various contact members, when actu-' ated, are used coil 26, wire order'to prevent the surreptitious short circuiting of one of the closed circuits in the line between the cabinet and loops, whereby forced entrance may be obtained without sounding the alarm. I have shown an open circuit of two wires without branches or taps. These wires are in a cable runnin throughout the building adjacent the close circuit wires and having the same appearance. This open circuit is independent of the bell circuit but is in series with a relay 27 which'is stronger than the relay 26. If a knife is used to remove the insulation from the closed circuit wires with the intention of shorting this circuit to shunt out one of the frangible loops to be thereafter .broken. There is an equal chance that the knife will close the open circuit, actuating the relay 27 to draw the armature 33 into engagement with the contact point 45, thus closing the alarm circuit.

When the normally open current flowsas follows: v Battery A, wire 30, .ground 31, ground32,

circuit is closed and 58 to the position indicated by mal position;

'tionary plates 62 and 63 respectively,

armature 33, contact point 34, wire 35, wire 66, then through the short circuiting means indicated by the broken lines in 67, wire 68, relay 27, wire 69, wire 40 and thenback to the battery. j I

As soon as the relay 27 is actuated to draw the armature upwardly and away from the relay 26, then engagement with the contact point 34 is broken, whereby the spring 41 functions to hold the armature in engagement with the contact point 45. As soon as the armature is drawn away from the contact point 34, then the coil is deenergized. Accordingly, only a single impulse is given by the relay 27 so that the alarm is sounded even though the closing means, such as a knife blade 67, is immediately removed from the open circuit wires. 7

It follows then that my invention embodies aclosed circuit, an open circuit, and an alarm circuit which is normally open, all of. which may be operated from a single source of electrical supply, such as the battery A. The normally open circuit formed by the wires 66 and 67 may, if desired, be connected to a butt, or rub contact adjacent a door, window, or other closure, which would close the contact the same as would any instrument used to cutthe wires.

The lock switch shown particularly in Figs. 2 and 3 is useful for rendering the system inoperative as when'the building isoccupie'd in the day time and freedom of all entrances is desired for making necessary repairs or adjustments, and for enabling the detection of any particular loop which may have been broken. WVhen it is desired to disconnect the alarm circuit, the lock switch is operated to move the contacts 57 the dotted line in Fig. 3. \Vhen these contact members are in the extreme left hand position, then the circuit to the alarm through the contactmember 49 is broken, while the -circuit through the members 57 and 58 is also broken. If the lock switch has been moved to make repairs then after such adjustments are made, the switch is returned to the nor- During the initial movement the contact 49 will engage the plate 51, so that if alarm circuit 1s completed and in working order the alarm will be momentarily sounded. This sounding amounts to no more than a single stroke orclick which informs the operator that the battery is active and thus provides a test for the strength of the current. still farther to the ri ht, contact is made between the members 57 and 58 and the stawhich shunts the disconnected enclosed circuit and energizes the coil 26, wherefore the armature is moved downwardly against the force of the spring to e ect engagement with point 34 whlch of course stops the alarm.

Thenif the switch is turned Since the lock switch is operable from a point outside the cabinet, then such movements may be effected without opening the lid of the cabinet, and therefore without dis-' points 63 and 62 respectively, provided there is no break in the closed circuit.

If however, there is a break in the closed circuit then when the lock switch is moved to the position shown in the full lines, the

alarm will be sounded. To determine then at which point the break is located, the key switch is again moved to the left to bring the contacts 57 and 58 into engagement with contacts 62 and 63 so as to close the circuit through the coil to the armature to the lower position. Then the lid of the cabinet is opened and one of the test switches such as switch 23 is closed, whereupon the lid of the cabinet is again closed and the lock switch is moved to the full'line position in Fig. 3. If the alarm is not sounded then the break in the closed circuit is in the loop controlled by the switch 23.

In view of the foregoing description, it will be seen that my invention is well adaptcd for maintaining an alarm system having a combined open and closed circuit, operable from a single battery, and that the opcrative devices may be satisfactorily housed in a small cabinet. Further, it will be seen that my invention permits the use of an open circuit, which may be wound in a cable with the wires of a closed circuit, and be so connected with relation to the opposed re- 7 lays that an attempt to short out the closed circuit would result in the possibility of closing the open circuit,..and in either case cause the alarm to be sounded.

1. In an alarm, a normally closed circuitand a normally open alarm circuit, a source of power, a switch, means whereby said switch may be moved first to close said alarm circuit to test the strength of the source of power, then moved to shunt the alarm cir cuit to render the alarm circuit inoperative and finally to break the shunt connection,

means including a relay connected with the switch and source of power operable to open the alarm circuit when said shunt connection is made and to close the normally closed circuit.

2. In combination, a normally closed circuit, a normally open alarm circuit, and an alarm controlled thereby, a source of electric power, a switch having movable contact points, means including cooperating contact points connected to the normally closed cirthen momentarily closed for testing the condition of said source of power and the nor reptitiously broken, the alarm will be sounded.

In testimony whereof, I hereunto aflix my signature.

GOTTFRIED F. GASSER.

G5 cuit and alarm circuit-so arranged that both I circuits may be first open, the alarm circuit 

